Production of cycloidal curves



Aug- 4,71'931- l.. K. BRAREN v 1,817,405

PRODUCTION oF cYcLorDAL cuRvEs Filed 4 sheets-sheet 1 JMW Aug. 4, 1931.

L. K. BRAREN ERODUCTION 0F CXCLOIDAL CURVES Filed Nov; 50, 192e 4 Sheets-Sheet 2 Y, bren inrmlyurew Aug. 4, 1931. L. K. BRAREN l 1,817,405

PRODUCTION OF CYCLOIDAL CURVES y Filed Nov. 30. 1926 4 Sheets-Sheet 5 J2 s1' 7, 71 96 t 46 sa 5 5 ly l .9 ji; 9.4

u :vl 73 i 1 -97\` L vw 11 a 1-4 *v W 2 'l 5 s s W 7 @C #was Aug. 4, 1931. L. K. BRAREN 1,817,405

`PRODUCTION OF CYCLOVIDAL CURVES y Filed Nov. 30, 1926 4 Sheevets--Sheeltl 4 Patented Aug. 4.,v 1931 UNITED STAT-Es PATENT vo r-'rlcn LonENz KONRAD Bauamt, or uUNIcH, e'EaxaNY,'assIGNon 'ro FRIEDRICH DECKEL, ,razIsroNsnEcnANIx UND vMascia INENBAIL or MUNICH, BAVARIA, GERMANY, a

FIRM

y PRODUCTION F CYGLOI'DAL -CUBVES Application led November 30, 1926, Serial No. 151,759, and in Germany December 5, 1925.

This invention relates to the product-ion of cycloidal curves and the object of my invention is to provide a method and means for generating accurately and rationally such curves. The term cycloidal curve in the following is meant to include epiand hypocycloids, epiand hypotrochoids of the prolate or curtate form and of all possible equidstants to the above curves as they may be lused for instance in different types. of gearing. My copending application gear transmission (now Patent No. 1,694,031, dated Dec. 4, 1928) shows how such curves may be used for a specific construction. According to -my invention the cutting tool and the work perform two circular movements in relation to each-other, whereby it is immaterial whether both these movements arehperformedby the same part or one by eac The turning movement around the axis of the s stem represents the continuous advance o the rolllng circle on the base circle, while the movement of the tracing point around the center of the'rolling circle is reproduced by a bodily circular movement of the whole part or of the tool. The

radius of this circular movement must be equal tothe distance of the tracing point ,to the center of the rolling circle. The angular velocities of both circular movements stand in the following relation.

radius of base circle i radius of rolling circle radius of rolling circle i formed by the work, for instance a disc, all

points of the disc describe cycloidal curves which are more or less deiqlfmed .In a certain distancefror'n'the center 0f the system, however, there isfdescribed the correct curve and thus it becomes possible to shape the disc to the desired curve by a tool operating at that distance from the center.

A rotating cylindrical cutter with the ceni curves. It is known that the normal of anyv point of the curve passes through the point of contact of the rolling circle with vthe base circle. When moving the rolling circle with constant velocity on the base circle, the normal passes with constant velocity on the base and also on a second circle. This second circle has been 4fou'ndto have a radius equal to the distance of the tracing point from the centerv of the rolling circle times radius of the base 4circle radius of the rolling circle The above facts are made use of in the following manner. Either the tool or the work or both are mounted turnably on an axis parallel to the axis of the system and passing through the path of the desired cycloidal curve and are connected lto an arm which is oscillated by a. crank moving with the angular velocity of the base 'or rolling circle. When moving the crank with the velocity of the rollingl the crank must e ual ey radius of the above mentioned secon circle. When moving the crank with the 'velocity of the base circle4 this radius must be equal to the radius of the base circle.

lA further object of my invention is to mount the tool on a slide for adjusting the circle the radius of tool in order to produce different equidistants to cycloidal curves. Thus also a wear -v of the tool may be compensatedfor. The tool ma perform axialI reciprocating strokes 1i e a shaper or a rotating tool may be used and the curve shape be produced on a cylindrical body by a. slow relative axial movement between tool and work showing as a spiral .path on the circumference. l

l scrlbed and claimed. -In order that this myV scale.

A further object of my invention is to provide a machine entirely automatic in its movement ermitting an operator to serve a number olf) machines.

The above and various other important improvements will be hereinafter full deinvention may be more readily understood reference is made to the accompanying sheets of drawings which show how the invention may be carried into practical effect.

Fig. 1- is a side view of a grinding machine adapted for this pu ose.

Fig. 21s a to view of t e grinding machine shown in ig. 1.

l Fig. 3`is a sectlon of the grindin machine shown in Figure 1 on an en arged Fig. 4 is a section of the work carrier on an enlarged scale.

Fig. 5 shows the drive for the workv carrier 1n a vertical section at right angles to the Figure 3.

Fig. 6 is an horizontal section of the same drive on a smaller scale.

Fig. 7 shows the drive for the tool slide on Figure 6 in a dierent position.A

Fig. 8 isv a vertical section throughA the tool slide. v

Fig. 9 is a diagram of the method of working.

Fig. 10 shows a prolate epitrochoid and the construction lines used in producing the curve. A i

Fig. 11 is a similar hypotrochoid.

The tool 1 on Figure 9 is mounted turnably on an vaxis 2. The work 3 performs a double movement. Once it is moved bodily by an eccenter 4 and it also turnsaround an 4axis 5 causing' thus points on the circumference of the disc 3 to describe a cyc'loidal path 6. The swinging movement of and shown in the tool 1 is controlledl by a llever 7 fastened' to the toolholde and by a dog 8 circling aroundthe axi f 5 andsliding in a guide 9 of the lever 7. The lines 10 indicate the extreme positions of the tool 1. In case the tool, as shown, does not operate in the point 2 where it would produce the ath 6 ut at a distance therefrom an equi 'stant 11 to the cycloidal4 curve is the result such as are used for instance for some sort of special' gearing of which one t is described my copendlng application :lgear transmission of the same date as e present application, now Patent No.

' 1,694,031, above mentioned.

In Figure 10 there is shown an e itrochoid and in igure 11v an hvpotrochoi of whicha is the base and t the rollin circle. The distance of the tracing point fig-o center of the-rolling circle is designated by e and r isa circ e of construction for the normal lines. The Greek letters a, y, etc.

m the: 1^

designate identical points on both curves,

while a', y', indicate the intersections of the normal with the base circle and a, y", with the circle of construction. Thus, it can readil b e seen that for a tool pivoted in the axis 0 ythe path a, y, the. rocking lever must be guided on the base circle a', y',

with the angularvelocity of vthe base circle and on the circle of construction a, y with the angular velocity of the rolling circle. A tool operatinginthe distance 8 on the inside or 6 on the outside of the pivot axisv of the tool carier, of course produces equi: distant curves which are designated by thel `(ll/l .YI/I all/l, 7 respectively. Instead of mounting the tool to oscillate back and forth the work holder may be as wellpivoted to perform the required features of constructions as for instance the arrangement and drive of the tool would have to be alteredcorrespondingly. The machine as described contains a base, a tool on a slide with dressing means, a drive for feeding the tool axially, a work carrier, means for oscillating thecarrier, and a drive for the tool carrier.

A slide 22 is held on a dove tailed guide on the base 21 (Figures 1, 2 and 3). 'A screw spindle 23' journaled in a bore of 'a hub 24 moves the slide up and down when the suporting nut 25 located in a web of the base 1s turned. The slide ma be adjusted by hand through a pair of bevel gears 26 of which one is fastened to the screw 23 and the other, not shown on the drawingsv to a shaft and a handwheel 27. The tool, a grinding wheel 20, is mounted in 'a well known manner in a bracket 28 which is mounted with a dovetailed guide on the slide 22. For dressing the wheel 20 to a: radius smaller than the smallest radius lof curvature of the curve to be produced there is rovided a diamond 31` in a holder 32 which is turnably mounted on a pin 33. The

pin is fastened to a small slide 34 (see also igure 8)' which carries a nut 35 in engage-` this manner always the same position. A

relative adjustment of the grinding wheel and the dressing tool is attained by aspiral gear 37 on a shaft 38, which is turned by a and wheel 39, after a nut 18 has been loosened frstwhich clamps a handwheel 30 and the tubular screw 19 to the screw 29. On the slide 22 there is provided a bracket 40 for an electromotor 41 which drives the grinding whee the belt passing over guide rollers 42 an An'arm 52 is mounted on a' vertical pivotv 53 fastened in an arm 56 of the base 21 (Figs. 3, 4 and 5).- v The arm 52 carries on top a work carrier 51 ina guide extending radially from the pivot axis 53. Similarly there is mounted below the arm 52 a bracket `54 in a radial guide. A main -shaft 55 is `journaled in the bracket`54 and in the work carrier 51. For driving the main shaft 55 there is provided a pulley 57 which is actuated by a pulley 58 located above the, machine, the driving belt passing over guide pulleys 60 on a swinging arm 59. lThe pulley -57 is fastened on a ,shaft 61 which carries also a gear 62 (Fig. 6). The latter stands in engagement with a gear 63 fastened to a bushing 64. A key in the hole of this bushing drives a shaft 65 without holding it axially YA worm 66 is rpart of this` gear 76 also fastened to the shaft 75 drives `a gear 77 over an idler gear 69 on a shaft 83 (see also Fig. 2). The gear 77 is fastened on a sleeve 78 which is journaled in a cover 79 of the tool carrier and provides a bearing in turn for the shaft 71. The upper enlarged end of the sleeve is provided with flats 80 and 81 over which an intermediate member 82 of a cross slide fits. This member 82 carries two faces'at right angles to the faces 80 and 81forming a guide for the upper part 85 of the cross slide the latter attaining thus free moveabilitysideways. A bushing'l 86 is fastened by screws to the part 85 and carries the work discs 87, a nut 88 clampingl the work. An eccentric sleeve 89v is fastene by a key 90 to the inner shaft 71. The bushing 86 turns, on the outside of this sleeve. A screw 91 in the end of the shaft 71 clamps the sleeve 89 by a washer 92 and provides thus an axial guide for the bushing 86. A cylindrical cover 93 is fastened on the bushing 86 for preventing dirt and grinding dust from entering. A similar cover 94 for the same purpose is fastened on the sleeve 78. To remove dead play there are provided brake shoes .9:5 which are pressed by springs 96 against the inside rim of the cover 94.

striction by the For the same purpose a brake disc 97 vis fastened on the upper end ofthe main shaft 55. The brake shoes and springs are not shown on the drawings being located at right angles to' the section.

-In this manner the work disc receives two distinct circular motions, a slow o ne throu h the gears 73, 74, 76, 69. and 77, the sleeve 8 and the cross slide arrangement and a fast one direct' throughthe eccentric sleeve 89,

which combined produce the desired shape of curve. An hypocycloidor hypotrochoid results with a turning movement of the shaft 71 and the sleeve 78 in the same direction andan epicycloid or epitrochoid withmovem'ents in` opposite directions. In order to producean hypofvcloid or hypotrochoid the gear 69 must be i the. gearY 76 brought indirect enga-gement with the gear 77.

sengaged or 'removed 'and y The oscillating movements of the work are v effected by a bushing 101 (Figures 3 and 5) which is fastened in a slide102 and can be adjusted to different distances from the center line of the main shaft 55. A member 103 for receiving the adjusting slide 102 is. `fastened on the main shaft55, A pin 104 forming part of a second slide 105 is guided by the bushing 101. The slide moves ina guide 106 which is held by an'intermediate piece 107 to the base 21 of the machine.

When turning the main shaft 5 5 the'bushing 101 moves in a circle of which the radius depends on the position ofthe slide 102. The pin 104 however on account of the reguide 106 can only move back and forth in a straight path. The components of the circular movement at right angles to this path are transferred to the.

arm 52 and the work 87 with the motion of a-swinging block linkage as shown in Figure 9.

In order to use the drive of the work for feedin alsovthe tool there is provided a plateli e projection 111 with a slot 112 on the arm 52 (Fig. 6). A bracket 114 is held by a screw 113 in this slot. This bracket carries on the end a bolt 115 which actuates a clutch 117 through a connecting rod 116. The oscillating movement is transferred in well known manner through rolling Vmembers 118 into an unidirectional movement of an inner member 119.

The amount ofoscill-ation may be varied considerably by changing the position of the bracket 114 in the slot 112. The inner member 119 is connected te the nut 25 by a tooth coupling 120 and causes thus the feeding motion of thetool. The tooth coupling y120 can be disengaged b an adjustable stop 124 on the slide 22 (Figure 1), a lever 122 on a shaft 123 transmitting the movement to a forked lever 121 which stands in-engagement with the inner member 119.

The coolant for the grinding wheel is delivered by a pump not shown. A lbasin 125 for catching the coolantl is provided with an opening 126 conducting it through the hollow shaft 53 and an opening 127 into the suction chamber of thepump.

Having now particularly described and ascertained the nature ofmy said invention I do not wish to be understood as limiting myself to the exact details of construction as obviously many modifications will rolling circle and with a radius equal to the distance of the generating point from the center of the rolling circle and the other a turning movement with the angular velocity of the base circle.

'2. In a device for producin cycloidal curves, a tool, a work carrier, an means for imparting two circular movements in substantially the saine plane to said. tool and work carrier in relation to eachother, the angular velocity of one movement being a multiple of the angular velocity of the sec- ,ond movement, the two circular movements in combination resulting in cycloidal curves.

3. In a device for producing cycloidal curves, a tool, a work carrier, means for imparting a bodil circular movement to said tool and worh carrier in relation to each other, and means for imparting a second relative turning movement to said tool and work carrier, said second movement being in substantially the same plane as the first movement, saidbodily circular movement and relative turning movement in A combination resulting in cycloidal curves.

4. In a device for producing cycloidal curves, aI tool, a work carrier, means for rotating said work carrier, and different means or imparting a secondbodily circular movement to said work carrier in substantially the' same plane as the rotary movement thereof, the rotation of the world carrier and the bodily circular movement thereof resulting in combination in cycloidal y curves.

5. In a devicefor producing cycloidal curves, a tool, a work carrier, means for rotatin said work carrier, 'and different means or imparting a bodily circular movement to said work carrier in substantially `the same plane as the rotary movement thereof, the angularvelocity of the second movement being a multiple of the, angular velocity of the first movement, the rotation of thework carrier and the bodily circular movement thereof resulting in combination in cycloidal curves.

6. In afdevice for producing cycloidal always normal to `the part of the curve worked upon.

7. In a device for producing cycloidal curves, a tool, a work carrier, means for moving said toolv` and work carrier m relation to each other to produce cycloidal curvesv by said tool on the work fastened to said work carrier, and a linka e for oscillating said tool and said wor carrier in relation to each other for holding the face of the tool always normal to the curve generated.

8. In a device for producing cycloidal curves, a tool, a work carrier, means for causing said tool and work carrier to perform two circular movements in relation to each other which in combination result in cycloidal curves, and a linka for oscillatin said tool and said wor carrier in relation to each other, the oscillating period being in time with one of the said circular movements.

9. In a device for producing cycloidal curves, a tool a work carrier, a drive for causing a bodily circular movement of said tool and said work carrier in relation to each other, another drivel for causing a relative turning movement between said tool and said work carrier, and al linkage for oscillating saidl tool and said work carrier in relation to each other, the oscillation being in time with the drive for the bodily circular movement.

10. In a device for producing cycloidal curves, a tool, a work carrier, a drive for causing a bodily circular movement of said tool and said work carrier in relation to each other, another drive for causing a relative turiiin movement of said tool and saidvwork carrier in relation to each other, said second turning movement representing the progress of the rollin circle on the base circle and said-first circu ar movement representing the rotation of the rolling circle,

av linkage, and a driver forming part of said the radius equals the distance of the generatin point from the center of the rolling circle imes radius o! the bue circle radius ol' the rolling circle l1. In a device for producing cycloidal curves, atool, a work carrier, a driving means for causing a bodily circular movement of said tool and said work carrier in relation to. each other, vdifferent driving with one of said driving means,

ments combining to have said tool describe p a cycloidal curve on the work fastened to said work carrier, a linkage, a driver forming part of said linkage rotating in time also forming 'part of said linkage operating together with said driver in transforming the circular motion of said driver into an. oscillating movement of said tool and Work carrier in relation to each other.

.12. In a device for producing cycloidal curves, for causing a bodily circular movement of saidywork carrier, different driving means for causing a relative turning movement of said work carrier, both said driving means rotating in fixed relation to each other, and a linkage, consisting of a driver connected to and rotating with one of said driving means and a stationary slide for causing an oscillating movement to be impressed upon said work carrier by the rotation of; said driver. v

13. In a device for producing cycloidal curves, the combination with a tool,- of a spindle, a sleeve rotatably mounted on said spindle, a work support'movable relative to said sleeve and operatively connected to rotate therewith, an eccentric portion on said spindle for giving said .work support.

a bodily rotative movement relative to the spindle, means. for rotating said spindle,'

and meansjfor rotating said sleeve relative to. said spindle, so that said tool will trace a cycloidal curve on a piece of work carried lby said work support.

for producing cycloidalf- 14. In a device curves, the combination with a tool of a frame pivoted to oscillate 'about an; axis, a spindle rotatably mounted on said frame, a sleeve rotatably mounted on said spindle, a work support movable relative to said sleeve and operatively-coiinected to rotate therewith, an eccentric portion on saidl spindle for giving said work support a bodily rotative movement relative to the spindle, means for rotating said spindle, means for rotating said sleeve relative to said spindle so that said tool will trace a cycloidal curve on' a piece of work carried by said work support, and means operated by the rotation of said spindle for oscillating said frame about said pivotal axis to kee the face of said tool normal .to said cyc oidal curve. I

15. In a device for producing cycloidal curves,4 the combination with a tool, of a frame pivoted to oscillate about an axis, a spind e rotatably mounted on -saidframe and adjustable toward and away from ysaida sleeve rotatably mounted on pivotal axis,

a work support movable relasaid spindle,

and a guide a tool, a work carrier, driving means tive to said sleeve -and operatively connected to rotate therewith, an eccentric portion on said spindle for giving said work support a bodily rotative movement relative to the spindle, said eccentric portion bein adiust-A able to vary the radius of said bo ily rotation, means for rotatin said spindle, and means for rotating sai sleeve relative to said spindle, cycloidal curve on a piece of .work carried by said work support.

16. A method of producing cycloidal curves in which a tool and a piece of work perform relatively to each other two circular movements of which one is abodily circular movement with an angular velocity equal to that of the rolling circle and with f a radius equal to the distance of the gen-` erating point from thecenter of the rolling circle, the other circular movement being a turning movement with the angular velocity of the base' circle, and in which method the face of the tool is always held normal.

to the curve generated.

17. A machine for producing a vcycloidal curve on the periphery of a disk, said machine comprising a tool for cooperation with said periphery, a work holder for holding said disk, means for causing said tool and work holder to move relatively .to each other through a bodily rotary movement having an angular velocity substantially e ual to Y 'substantially equal to the relative angular `velocity between the theoretical base circle and a line drawn from the vcenter of the base circle to the center of the rolling circle.

In testimony whereof I hereunto aix my signature.

LORENZ KONRAD BRAREN.

so that said tool will trace a 

